Regression matrix

tools/test-all-backends.py is the pass / fail gate for the whole backend matrix — sister to tools/macbook-benchmark-all-backends.py, which is the perf benchmark.

Each backend declares advertised capabilities (transcribe, json-output, stream, beam, best-of-n, temperature, word-timestamps, punctuation, vad, lid, tts-roundtrip, translate, voice-cloning). For each capability, three tiers exist: ignore / smoke / full. Profiles set defaults; per-capability flags override. The three profiles are smoke (default — transcribe only), feature (every capability at the smoke tier) and full (every capability at the full tier).

# Quick smoke (transcribe-only on the JFK reference)
python tools/test-all-backends.py

# Full feature matrix (every advertised capability)
python tools/test-all-backends.py --profile=feature

# Subset by name or capability
python tools/test-all-backends.py --backends parakeet,kyutai-stt
python tools/test-all-backends.py --capabilities stream,beam

# Override one capability tier
python tools/test-all-backends.py --vad=full --transcribe=full

Cache modes — --cache-mode={keep,ephemeral}

Two operational profiles for how the script handles model files:

Mode	When	Behavior
keep (default)	local dev, bandwidth-limited	Downloads persist across runs in --models PATH.
ephemeral	tight-disk runners (Kaggle, cloud), bandwidth-cheap	After each backend's tier tests complete, deletes files we downloaded this run. Pre-existing files are never touched. Reference models (whisper-tiny for LID, parakeet for TTS-roundtrip ground truth) are pinned and kept until end of run.

Kaggle invocation:

python tools/test-all-backends.py \
  --models /kaggle/working/models \
  --cache-mode=ephemeral \
  --profile=feature

The reference downloads (~500 MB total) stay resident; each big backend (1–4.5 GB Q4_K) comes + goes one at a time, keeping peak disk to ~5 GB even though the registry's 62 backends total ~85 GB of approx_size_mb hints.

Skip-missing — --skip-missing

Disables HF downloads entirely. Backends without a local model on disk are reported as NO_MODEL (not FAIL). Useful for CI runners that should fail on regression but not on missing models.

Pre-download disk-space check

Each Backend declares an approx_size_mb hint. Before downloading, the script checks shutil.disk_usage(models_dir).free against approx_size_mb + 2 GB margin; if low, it skips the download (reports SKIP — need ~X MB, only Y MB free) instead of half-filling the disk.

Companion benchmark suite

For perf rather than pass / fail, see tools/macbook-benchmark-all-backends.py (and tools/kaggle-benchmark-all-backends.py for the Kaggle T4 benchmark — results live in PERFORMANCE.md).